N/A
This invention relates to an alarm circuit for a hearing aid, which can provide advance warning that the battery is approaching its end of life, and/or function as an increased-audibility alarm to provide wake-up or other-purpose alarm signals to the hearing impaired wearer. Unlike other increased-audibility alarms for the hearing impaired, the alarm circuit of the invention is private and not annoying to those around the wearer.
There are many low battery detector circuits on the market. These typically include a plurality of discrete components or are contained in a separate integrated circuit designed for that purpose, and typically operate in a binary manner: No output until the battery voltage drops below the detector threshold, then full output in the form of a warning light, series of beeps, or the like.
The prior art also includes arrangements particularly for testing batteries used in conjunction with hearing aids. Oticon Corporation manufactures a behind-the-ear hearing aid incorporating a battery test switch, with an LED readout, eliminating the need for a separate battery tester. A low-battery indication is built into the hand-held remote control transmitter used with Widex Corporation""s xe2x80x9cQUATROxe2x80x9d remote-controlled hearing aids to monitor the battery in the transmitter although not the one in the hearing aid itself.
This invention was evolved with the general object of providing a simple and effective arrangement by which the user of a hearing aid might be alerted to low battery or other alarm conditions.
Important aspects of the invention relate to the recognition of problems with prior art arrangements and the causes thereof. The space and circuitry requirements of low battery detector circuits of the prior art are such that they cannot be practically included in a hearing aid. In my aforementioned application, of which this is a continuation-in-part, a circuit is disclosed which is such that it can be incorporated in a hearing aid, having the important advantage that it can use the existing audio amplifier circuitry of the hearing aid for producing an audible indication of the low battery. That circuit has the additional advantage of providing a warning whose loudness and signal frequency progressively increases as the battery falls lower and lower below the preset threshold. It is quite simple and can be added to a hearing aid integrated circuit amplifier with little additional area required on the chip.
It is has been found that there are instances in which a user may desire to disable the warning signal until such time as he may conveniently change the battery, or in which the user may desire additional features and, in accordance with an important feature of the invention, the user of a hearing aid is provided with a manual means of disabling the low battery warning signal once it has been heard.
Another important feature relates to an arrangement with provides the user with the option of using the on-off switch of the hearing aid as the disabling switch, in order to avoid the additional space and expense required by a separate disabling switch.
A further feature of this invention relates to the provision of an automatic means of limiting the percentage of time the low-battery warning is audible, in order that it not become annoying before he has time to change the battery.
Still another feature of the invention relates to the provision of a wake-up or other alarm that is easily heard privately by the hearing impaired wearer, but which is not disturbing to those around him or her.
The invention also provides automatic means of increasing the audibility of the warning or alarm signal until such time as the hearing aid wearer signals that he has heard the signal and turns off the alarm.
These and other objects, features and advantages will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings.